Giliastrum

Giliastrum is a poorly known genus of nine species native to arid regions of southwestern North America and South America (Argentina, Bolivia, Chile, Peru).

Giliastrum is distinguished from the Bryantiella by having yellow instead of white pollen.

Biogeography

Giliastrum is most diverse in northern Mexico. It occurs as a disjunct in the Andes.

worldwide distribution of Giliastrum

worldwide distribution of Giliastrum

Taxonomy (* indicates South American taxa)

  1. Giliastrum acerosum (A. Gray) Rydb.
  2. Giliastrum foetidum (Gillies) J.M. Porter*
  3. Giliastrum gypsophilum (B.L. Turner) J.M. Porter
  4. Giliastrum castellanosii J.M. Porter*
  5. Giliastrum ludens (Shinners) J.M. Porter
  6. Giliastrum insigne (Brand) J.M. Porter
  7. Giliastrum incisum (Benth.) J.M. Porter
  8. Giliastrum purpusii (K. Brandegee) J.M. Porter
    • G. purpusii (K. Brandeegee) J.M. Porter subsp. platylobum (I.M. Johnst.) J.M. Porter
    • G. purpusii (K. Brandeegee) J.M. Porter subsp. purpusii
    • G. purpusii (K. Brandeegee) J.M. Porter subsp. stewartii (I.M. Johnst.) J.M. Porter
  9. Giliastrum rigidulum (Benth.) Rydb.

KEY TO GILIASTRUM (modified from Turner 1994)

1. Corolla 4-7 mm long; basal leaves simple or deeply serrate…G. incisum
1′. Corolla 8-20 mm long; basal leaves dissected or pinnately lobed
2. Calyx tube 1/3 of the total calyx length (G. purpusii)
3. Corolla 8-9 mm long…G. purpusii stewartii
3′. Corolla 10-13 mm long
7. Ultimate leaf divisions broad…G. purpusii purpusii
7′. Ultimate leaf divisions narrow…G. purpusii platylobum
2′. Calyx tube 1/3 of the total calyx length or more
4. Corolla 18-22 mm long, 22-32 mm broad…G. insigne
4′. Corolla 10-18 mm long, 15-20 mm broad
5. Woody perennial, basal leaves deciduous
8. Corolla about 10 mm long, corolla lobes about 4 mm long, North America.
9. Leaves with divisions linear, acerose…G. acerosum
9′. Leaves with divisions broader, not acerose…G. rigidulum
8′. Corolla > 11 mm long, corolla lobes > 7 mm long, South America
10. Corolla pale blue, less than 15 mm long, lobes acute; rare…G. castellanosii
10′. Corolla pink, usually > 15 mm, lobes obtuse…G. foetidum
5′. Annual or lax perennial, the basal leaves usually persisting
6. Basal leaves with deeply incised simple lobes; apices acute…G. gypsophilum
6′. Basal leaves pinnately lobed or dissected; ultimate segments ovate to oblanceolate…G. ludens

References

Porter, J. M. 1998. Nomenclatural changes in Polemoniaceae. Aliso 17: 83–85.

Porter, J. M. and L. A. Johnson. 2000. A phylogenetic classification of Polemoniaceae. Aliso 19: 55-91.

Turner, B. L. 1994. Taxonomic overview of Gilia, sect. Giliastrum (Polemoniaceae) in Texas and Mexico. Phytologia 76: 52–68.

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